Digital Beamforming Method for Wideband Reception Based on Deskewing and Twice Delay

Abstract

The invention discloses a broadband receiving digital waveform formation method based on dechirp processing and two-time time delays. A DDS is designed by use of a polyphase processing technology in an FPGA, by use of two double-accumulators and a CORDIC algorithm, digital band-based signals of broadband chirp signals are generated, and then interpolation filtering upconversion digital-to-analog conversion is carried out; a digital time delay filer is designed; by use of externally input reference clock signals and frequency agility local oscillator signals, first and second local oscillator signals are generated; an antenna array receives radar echo signals and performs frequency mixing filtering with the first local oscillator signals and the second local oscillator signals through amplitude-limiting amplification; and synthesizing is carried out after digital time delay processing on the signals in a frequency domain so as to form a receiving digital wave beam. According to the invention, by use of phase control and continuously variable digital time delay control, broadband dechirp local oscillator signals are generated, and receiving waveform formation control of broadband signals is realized.

Description

technical field [0001] The invention relates to a broadband receiving digital beamforming method based on de-skew processing and two time delays, and belongs to the technical field of array signal processing. Background technique [0002] Phased array radar can complete various tasks such as target search, tracking, and guidance, so it is widely used in fields such as multi-target ballistic measurement, air defense warning, and multi-target tracking and guided weapon systems. Requirements such as large airspace, multiple targets, and anti-jamming urge radar to develop in a digital direction. Digital array radar is the direction of future phased array radar technology development. The requirements for imaging and identifying targets have prompted radars to use wideband and high-resolution signal waveforms. For digital arrays of broadband signals, due to the existence of aperture transit time, only phase control cannot effectively form beams and control beam pointing. In ord...

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Problems solved by technology

[0009] a. The delay resolution of the digital delay line cannot meet the phase accuracy requirements of digital beam steering, and digital delay and phase compensation need to be performed at the same time;

[0010] b. Limited delay resolution, resulting in wideband signal side frequency phase errors, deteriorating the sidelobe performance of wideband digital beams

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